CREEP-BEHAVIOR OF DISPERSION-STRENGTHENED AL-ALLOYS

The creep behaviour is determined for the powder metallurgical Alumini um-Alloys AlSi(2)0, AlSil2Fe5, AlSi20Fe5, AlMg1, AlMg2, AlMg4, AlCuMg1 and AlMgSi1 at 300 degrees C and 400 degrees C. The tests were carrie d out on a non-strengthened version of these alloys as well as on disp ersion strengthened versions with mass content of C between 0 and 1% a nd O between 1 and 2%. The increase of the creep strength caused by di spersoids is found to be mostly independent on the creep life. The val ue of the strength increase is mainly a function of the volume fractio n of the dispersoids and less dependent on the matrix material. The in crease of creep strength is accompanied by a serious reduction in the creep fracture elongation. Failure occurs by spontaneous fracture duri ng the secondary or early tertiary creep stage at low values of strain .